This invention relates to a trash pick-up truck comprising a truck body, a cowl mounted on the truck body back and defining a collecting pan at its bottom, a passageway between the cowl and the truck body restricted by a partition wall at its top, a movable plate and a plate-like pressure extension articulated thereto for transfering and compacting trash, from the collecting pan into the truck body through said passageway, and a device for supporting and guiding said plate on the cowl inside.
As is known, to transfer trash from the collecting pan into the truck body, a movable plate is used which is supported in a guided manner inside the cowl and has a plate-like pressure extension or paddle articulated thereto.
The coordinated cyclic movements of the plate and its extension by appropriate motor means provide the desired transfer of the trash material from the collecting pan into the truck body and its concurrent compaction.
In this respect, owing to the considerably large magnitude of the forces brought into play during the trash transfer step, and especially during the trash compacting step, it becomes necessary to have the movable plate supported and guided in an adequately robust manner.
An example of a truck as indicated is described in U.S. Pat. No. 4,042,134. The movable plate supporting and guiding arrangement is therein a rod-type linkage forming two articulated quadrilaterals which guide the plate along an arcuate path facing the passageway between the cowl and the body with its concave side. While performing satisfactorily from the standpoint of its strength, that truck has a disadvantage originating from the very path travelled by the plate and pressure extension. The movable plate must be given an arcuate profile shape in order to keep close to the partition wall and prevent trash from flowing upwards, and the collecting pan bottom shape is, in turn, required to conform with the path travelled by the pressure extension, and this by means of two consecutive arcuate sections having oppositely directed curvatures and forming, accordingly, an angle therebetween.
It follows that as the plate-like extension travels the pan profile to empty the pan of the trash therein and transfer such trash into the truck body, the trash material is conveyed in a discontinuous manner and allowed to trip over the sharp angled intersect line.
Italian application No. 21515-A/82 by this same Applicant discloses another example of a truck as indicated, wherein the movable plate is supported by a rod-type linkage forming two articulated quadrilaterals which guide the plate along an arcuate travel path facing the passageway with its concave side. This prior approach, additionally to providing adequate strength, does provide for the pressure extension to travel through two consecutive arcs having concurrent curvatures and merging, therefore, with each other in a continuous fashion. Thus, this prior approach enables the trash collecting pan to be emptied without snags.
However, a prerequisite thereof is that the plate be given an arcuate profile in order for it to keep close to the partition wall and prevent the upflow of trash.
It also has the disadvantage of taking up an excessively large proportion of the cowl useful volume, thereby restricting the space available to accommodate the trash material when large-size containers are emptied into the pan. Lastly, the reaction to the trash compacting force toward the truck body, due to the large forces acting through the double pair of linkage rods whose fixed ends are pivoted to the rearward cowl portion, requires a high strength anchoring construction, which reflects unfavorably on the weight of the rear region, thereby the weight distribution to the truck axles is also affected adversely.